Effects of Rainfall and Temperature Variability on Cocoa Production in the Dormaa West District of the Brong-Ahafo Region, Ghana

Abstract

Climate change and variability are having severe impacts on agriculture production and food security, with yields from rain-fed agriculture in most developing countries projected to half by 2020. One such liable crop is cocoa (Theobroma cacao). This study used a time series statistical approach to measure variability in two weather parameters: temperature and precipitation, with a view to highlighting the effects on cocoa outputs from Dormaa West District. Data used was from the Ghana Meteorological Agency and the Ghana Cocoa Board for a 25-year period (1991 to 2015). The results suggest that there has been a 28.1% and 0.9% variability in average rainfall and temperature trends respectively for the period of 1991 to 2015. The variability in only rainfall accounts for 25.2% of the variations whereas variability in the only temperature accounted for 10.0% of the variations in cocoa outputs. From a general linear regression model, a combined effect of rainfall and temperature was shown to account for 25.3% variations in cocoa outputs for Dormaa West District. If trends in rainfall and temperature are to remain the same the effects of temperature on cocoa production may be limited by the increasing rainfall amount and rainfall months by making up for soil moisture losses. The study, therefore, recommends the need for programs that discourage forest depletion in the district to help boost the local average rainfall amounts to make up for soil moisture losses due to evaporation. A wider geographical spatial spread that will include other climatic variables (sunshine and humidity) should be analysed and modelled. This will help identify cocoa producing areas that are highly vulnerable to harsh weather conditions, for which farmers in those areas must adopt some specific and efficient measures to minimize their vulnerability.